- A
A single-region Spanner instance with a read replica in another region.
Why wrong: Read replicas are not synchronous and do not provide automatic failover.
- B
A multi-region Spanner instance with one read-write region and two read-only regions.
Why wrong: Read-only regions do not vote in writes, so a single read-write region means a regional failure stops writes.
- C
A dual-region Spanner instance using default leader placement.
Why wrong: Dual-region configurations (e.g., nam5) provide synchronous replication but may have higher write latency and still meet RTO requirements.
- D
A multi-region Spanner instance with two read-write regions and one witness region.
Correct: a multi-region instance with at least two read-write regions can achieve synchronous replication and automatic failover within seconds.
PCDOE Practice Question: Design for Reliability, Scalability, and Disaster Recovery
This PCDOE practice question tests your understanding of design for reliability, scalability, and disaster recovery. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
You are designing disaster recovery for a globally distributed application using Cloud Spanner with a multi-region configuration. The application requires an RPO of 0 and an RTO of less than 5 seconds in the event of a full region failure. Which Spanner configuration provides these guarantees?
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
A multi-region Spanner instance with two read-write regions and one witness region.
A multi-region configuration with a leader region and at least two voting regions provides synchronous replication and automatic failover. Regional failover occurs within seconds, preserving zero data loss.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
A single-region Spanner instance with a read replica in another region.
Why it's wrong here
Read replicas are not synchronous and do not provide automatic failover.
- ✗
A multi-region Spanner instance with one read-write region and two read-only regions.
Why it's wrong here
Read-only regions do not vote in writes, so a single read-write region means a regional failure stops writes.
- ✗
A dual-region Spanner instance using default leader placement.
Why it's wrong here
Dual-region configurations (e.g., nam5) provide synchronous replication but may have higher write latency and still meet RTO requirements.
- ✓
A multi-region Spanner instance with two read-write regions and one witness region.
Why this is correct
Correct: a multi-region instance with at least two read-write regions can achieve synchronous replication and automatic failover within seconds.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Detailed technical explanation
How to think about this question
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
- Use explanations to understand the rule behind the answer.
TExam Day Tips
- Underline the problem statement mentally.
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A cloud solutions architect for a retail company is evaluating services for a new workload. The correct answer here reflects best practice for the specific scenario described — not a general cloud recommendation. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Cloud exam questions reward reading the constraint carefully: the same technology can be right or wrong depending on the use case.
What to study next
Got this wrong? Here's your next step.
Identify which PCDOE exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
- →
Design for Reliability, Scalability, and Disaster Recovery — study guide chapter
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Design for Reliability, Scalability, and Disaster Recovery practice questions
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FAQ
Questions learners often ask
What does this PCDOE question test?
Design for Reliability, Scalability, and Disaster Recovery — This question tests Design for Reliability, Scalability, and Disaster Recovery — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: A multi-region Spanner instance with two read-write regions and one witness region. — A multi-region configuration with a leader region and at least two voting regions provides synchronous replication and automatic failover. Regional failover occurs within seconds, preserving zero data loss.
What should I do if I get this PCDOE question wrong?
Identify which PCDOE exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Last reviewed: Jul 4, 2026
This PCDOE practice question is part of Courseiva's free Google Cloud certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the PCDOE exam.
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